They will absolutely issue risky orders over a political agenda - see the current "red flag laws" that are being enforced around the country. They know most people don't want to go down the road of defending their rights the old fashioned way - yet.They may not be friendly to gun owners, but are they willing to order their officers to do what may get them killed to serve a political agenda? What they want to do, can do, and will do aren't the same thing. In other parts of the country I would agree with you. Here in OK I don't see it happening.
As for here in Oklahoma, it was the Oklahoma National Guard that did much of the confiscating in the suburbs (read that SAFE areas) of New Orleans after Katrina; I guess didn't have the balls to try it downtown where the REAL action was taking place, so they picked on the peaceful suburbanites just protecting themselves and their property. LEOs and military will do exactly as they're told - the bluster about "I'll refuse orders" from either of them is about as likely as the army of overweight 50-somethings in Hoverrounds kicking off the boogaloo. Certainly some may turn in their badges, but most will be at the front doors of law-abiding citizens, like it was just another warrant for anything else. It's the local sheriffs departments where the people might have an ally. But many of the local municipal blue line club - and possibly state troopers - will follow orders, just like the Stasi, NKVD, and Gestapo before them, as will most in the military. People are people, and history repeats. The United States isn't special in that regard - especially since the U.S. is now just "the United States in Name Only".